Typewriting machines – Including adjustment for optimum printing plane – Responsive to thickness of record-medium
Reexamination Certificate
2002-03-21
2004-02-17
Hirshfeld, Andrew H. (Department: 2854)
Typewriting machines
Including adjustment for optimum printing plane
Responsive to thickness of record-medium
C400S055000, C400S103000, C101S071000, C101S091000
Reexamination Certificate
active
06692166
ABSTRACT:
BACKGROUND OF THE INVENTION
Field of the Invention
The invention relates to a franking machine having a clamping device which can be driven via a drive device and by means of which an item of mail to be franked is securely clamped against a stop element. The clamping device comprises a clamping unit, which is provided for interacting with the item of mail, and a gearing device, which is connected to the clamping unit and the drive device and is intended for displacing the clamping unit in the direction of the stop element.
Conventional franking machines may be subdivided roughly into two groups depending on the volume of mail that is to be processed. The franking machines which are designed for a relatively large amount of mail are usually equipped with a transporting mechanism for the letter which is to be processed. In contrast, in the case of franking machines for a relatively small amount of mail, for example in the range of fewer than 20 to 30 letters per day, the letter usually has to be introduced and removed manually.
In order to ensure reliable positioning of a letter in relation to the printing head during printing of the franking mark, a clamping device is usually provided in the case of the franking machines wherein letters are fed manually, the clamping device clamping the letter against a stop plate, in order to fix it, during the printing operation. Provided in this stop plate is a printing window through which the printing head can print the letter with the franking mark.
In this context, it usually has to be ensured that it is possible to process letters of different thicknesses over a certain range. The maximum thicknesses to be processed here are usually in the region of 10 mm (0.4 in). It is thus necessary for the clamping mechanism and/or the drive thereof, to be configured such that they can compensate for different letter thicknesses.
U.S. Pat. No. 6,007,178 (see European published patent application EP 0 825 563 A2) discloses a franking machine of the generic type. There, the thickness compensation is achieved in that the clamping plate which presses the letter against the stop plate is pressed against the letter by two helical springs supported on the base of the franking machine. Depending on the thickness of the letter, a corresponding excursion of the helical springs is produced here. The drive device via which the clamping device can be opened and closed is coupled to the clamping plate via a rocking lever, of which the end which is directed away from the clamping plate runs on a cam plate, connected to the drive device. The drive device, rather than applying the clamping force, applies the force for opening the clamping device counter to the spring force of the helical springs. With each action for securely clamping the letter, the drive device always executes a predetermined drive displacement which corresponds to half a revolution of the cam plate.
This configuration, however, first of all has the disadvantage that, as a result of the helical springs having to be supported on the base of the franking machine, the clamping mechanism takes up a comparatively large amount of space in the interior of the franking machine, as a result of which the installation space taken up by the franking machine is increased overall.
This is not particularly desirable, not least from an esthetic point of view. It is precisely in relatively small offices or the like, for which this type of franking machine is intended, that there is often also a problem with space, with the result that, for this reason as well, the aim is to achieve the smallest possible configuration.
A further disadvantage of this known configuration is that the clamping force achieved varies to a very pronounced extent depending on the thickness of the letter which is to be clamped. Depending on the nature of the letter, the latter is then pressed into the printing window to a more or less pronounced extent, this resulting, in some circumstances, in a greatly varying distance between the printing head and letter, which may have an adverse effect on the printing result.
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide a franking machine with a clamping device for a piece of mail, which overcomes the above-mentioned disadvantages of the heretofore-known devices and methods of this general type and which provides for a franking machine with the smallest possible clamping configuration along with a low variation in the clamping force.
With the foregoing and other objects in view there is provided, in accordance with the invention, a franking machine, comprising:
a clamping device configured to clamp an item of mail to be franked against a stop element;
a drive device for driving the clamping device;
the clamping device including a clamping unit configured to interact with the item of mail, and a gearing device connected to the clamping unit and the drive device for displacing the clamping unit in a direction towards the stop element; and
the clamping unit and/or the gearing device having an elastic compensation section, the compensation section, upon a predetermined drive displacement of the drive device, compensating for different thicknesses of the item of mail by elastic deformation of the compensation section.
The invention is based on the technical teaching that a small franking machine is obtained if the clamping unit and/or the gearing device have/has at least one compensation section which is designed elastically such that, in the case of a predetermined drive displacement of the drive device, compensation for different thicknesses of the item of mail is provided by elastic deformation of the compensation section.
By virtue of the compensation mechanism being integrated according to the invention in the clamping unit and/or the gearing device, it is possible, in contrast to the known franking machine, to save a considerable amount of installation space, which is then available for the arrangement of other functional units of the franking machine, as a result of which a smaller franking machine is advantageously achieved.
Furthermore, by virtue of the compensation section being arranged and/or configured in a suitable manner, it is possible to achieve a configuration with a considerably lower variation in the clamping force for different thicknesses of items of mail.
It is thus readily possible for the compensation section to be of a sufficiently long length, which results in its elastic deformation behavior having a smooth characteristic curve, which in turn results in a low variation in the clamping force, even in the case of relatively large thickness variations, i.e. relatively large variations in the clamping displacement. It is also possible, in addition, for the compensation section to be arranged at a large distance from the clamping device in a region which, throughout the clamping movement, is only subjected to relatively small deflections in any case, with the result that, with the elastic deformation behavior of the compensation section having a sufficiently smooth characteristic curve, as mentioned above, comparatively small variations in the clamping force are produced.
A further advantage of the configuration according to the invention is that, by virtue of the compensation mechanism being integrated in the clamping unit and/or the gearing device, it is always possible for there to be a force-fitting or form-fitting connection between the links of the active chain, while that end of the rocking lever of the known franking machine which interacts with the cam plate, depending on the thickness of the item of mail which is to be processed, during the secure-clamping operation, lifts off from the cam plate to a more or less pronounced extent. This is both advantageous in terms of noise and favorable in terms of the wear to which the clamping mechanism is subjected.
The compensation section may be arranged as desired within or on the clamping unit and, in addition or alternatively, within or on the gearing device.
In the case of variants of the frank
Ansell Iain
Brace Steven Roland
Francotyp-Postalia AG & Co.
Ghatt Dave A.
Greenberg Laurence A.
Hirshfeld Andrew H.
Locher Ralph E.
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